I still get shocked at the level of closure here for Good Friday, in Birmingham for years we worked Good Friday and had Tuesday off instead, I never even knew it was a special day. 2 years ago I stayed in the city for Good Friday and everything in deed was shut. The only place to eat was the major hotels and they charged 15% extra for drinks and meals, and with Anzac day as well, Adelaide is shut for 4 days out of the 5.
Even this year we have tried to go out with friends for Good Friday, and Outback jacks other places we tried are shut. Apparently on Good Friday a lot of Adelaidians don't eat meat, never heard of this before, but i'm not religious.
There are places to go, and usually the more rural or suburban the better the chance.